Continuous treatment apparatus

ABSTRACT

A continuous treatment apparatus is provided that resists thermal shock and treatment gases and correctly transfers treated objects. An urging mechanism  9  that urges a treated object w is adapted to transfer a treated object w by reciprocating rack member  91  using a pinion  92  in separating compartments  6  between treatment chambers  1, 2, 3 , and  4 . This arrangement eliminates the need to install rack members  91  and pinion  92  in a severe atomsphere.

FIELD OF THE INVENTION

[0001] The present invention relates to a continuous treatment apparatusthat offers several features that make it ideal for various treatments,including vacuum dewaxing, sintering, quenching, powdering, brazing,welding, coating, surface treatment, heat treatment and hot pressing,etc.

BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT

[0002] A continuous treatment apparatus is designed to pass an object tobe treated through a plurality of treatment chambers to apply apredetermined treatment to the object in a sequence of steps. A pusherchain type transfer apparatus adapted to drive a chain using sprocketsis commonly used to transfer an object to be treated from one treatmentchamber to another.

[0003] However, because the ends of the chain of a transfer apparatus ofthis type are moved forward to a position at which the chain passesthrough treatment chambers, part of the pusher chain is exposed to hottreatment gases at the position, so that the chain is liable to beadversely affected by thermal shock, treatment gas, etc. The sprocketsare also adversely affected by thermal shock, treatment gas, etc.because they are disposed in the treatment chambers. The longer atreated object, the farther the pusher chain is moved forward.Accordingly, transfer performance tends to degrade. These problems caneasily lead to shorter apparatus life, frequent maintenancerequirements, and impaired reliability.

SUMMARY OF THE INVENTION

[0004] To solve the above-described problems, the present inventionprovides a continuous treatment apparatus adapted so that a treatedobject can be transferred from a treatment chamber to the next treatmentchamber using urging mechanisms between a plurality of treatmentchambers, wherein the urging mechanisms have the rack members that canmove in the direction of transfer, a pinion which drives the rackmembers and latching means for selectively engaging the rack memberswith the treated object; and wherein the rack members are not onlyengaged or disengaged with the treated object using the latching means,but reciprocated between adjacent treatment chambers through the pinionto transfer the treated object from one treatment chamber to another.

[0005] Because the urging mechanism transfers a treated object byreciprocating rack members between the treatment chambers, the rackmembers and pinion do not need to be installed in the treatmentchambers. Thus, rack members and pinion are less likely to be exposed tohot treatment gas, reducing the likelihood of damage resulting fromthermal shock and exposure to treatment gas and ensuring stableoperation for extended periods. Urging even a long treated object aplurality of times, with the latching means engaged with the object at adifferent position, allows efficient transfer of the object withoutlarge rack members.

[0006] In the above structure of the present invention, the rack membersare provided in pair and a pinion is engaged with the rack members atthe same time and the following operation is repeated: while one of therack members moves forward to transfer a treated object, the other movesback in preparation for the next transfer, and vice versa.

[0007] It is preferable that the latching means of the present inventionis provided at a plurality of positions along the direction of transferof a treated object by the rack members in the above structure.

[0008] And also it is preferable that the latching means of the presentinvention is engaged with a treated object at a plurality of positionsalong the direction of transfer of the treated object.

[0009] To make closing the treatment chambers compatible with propertransfer of a treated object without preventing the mechanisms frominterfering with each other, it is preferable that each treatmentchamber be opened or closed by a lid, that rack members move along thetransfer rail, which links adjacent treatment chambers with the lidsopen, and that it is possible to perform the following oppositeoperations around the shaft: (1) when the lid is opened, it is withdrawnto a position at which it does not interfere with the transfer rail orrack members; and (2) when the lid is closed, the transfer rail and rackmembers are withdrawn to a position at which the rail and rack membersdo not interfere with the lid.

[0010] It is desirable that the lid, the transfer rail, and the rackmembers of the present invention are installed and withdrawn using acommon rotating shaft.

[0011] A rod of the present invention is preferred to be housed in therotating shaft, and the rod ascends or descends to open or close thelid.

[0012] In the present invention, it is suitable that a pinion isconnected with the rod, and the rod can be rotated without beingprevented from ascending and desceding.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a schematic general cross-sectional view showing anembodiment of the present invention;

[0014]FIG. 2 is a partially enlarged view of the embodiment in FIG. 1;

[0015]FIG. 3, a counterpart of FIG. 2, illustrates operations;

[0016]FIG. 4 is a partial enlargement of FIG. 2;

[0017]FIG. 5 is a top view, with a rack and its surroundings enlarged;

[0018]FIG. 6 is a partial cross-sectional view of the embodiment in FIG.5;

[0019]FIG. 7 illustrates operation of the embodiment in FIG. 5;

[0020]FIG. 8 illustrates operation of the embodiment in FIG. 5;

[0021]FIG. 9 shows a variation of the present invention;

[0022]FIG. 10 shows another variation of the present invention; and

[0023]FIG. 11 shows still another variation of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Referring now to the attached drawings, an embodiment of thepresent invention is described below.

[0025] As shown in FIG. 1, a continuous treatment apparatus, which isused as a so-called continuous dewaxing/sintering furnace, has fourtreatment chambers that are disposed thus along the path of a treatedobject w: a preparing chamber 1, a dewaxing chamber 2, a sinteringchamber 3, and a cooling chamber 4 in this order from the leading end. Alid 5 is provided at an opening 5 a that is made as an inlet and outletof each of the treatment chambers 1 through 4. A separating compartment6, which is closed by lid 5, is formed between chambers 1 and 2, betweenchambers 2 and 3, and between chambers 3 and 4.

[0026] A transfer rail 7 is provided in separating compartment 6. Usingan opening mechanism 8, the transfer rail 7 is driven together with lid5. As shown in FIG. 3, the lid 5 can be withdrawn so that the lid 5 doesnot interfere with the transfer rail 7 when it opens. As shown in FIG.1, the transfer rail 7 can be withdrawn so that the transfer rail 7 doesnot interfere with the lid 5 when it closes.

[0027] Specifically, the opening mechanism 8 has a hollow rotating shaft81, a rod 82, a drive link 83, a bracket 84, and an L-shaped link 85, asshown in FIGS. 2 through 4. The rotating shaft 81 has a slit 81 a in itspart and is inserted through the bottom into a separating compartment 6.The rod 82 is housed in the rotating shaft 81 to move up and down, andthe end thereof is extended upward through the slit 81 a. The drive link83 is supported at the center of the rod 82 to cross the rod andprovided at both ends with horizontally protruding pins a 83 a. Thebracket 84, which passes through a slit 81 a, is installed tohorizontally rotate together with the rotating shaft 81. The L-shapedlink 85 is pivoted at its center on the bracket 84 and provided at itsbase end with a groove 85 a into which the pin 83 a slides and fits. Thetransfer rail 7 is secured to the rotating shaft 81. The lid 5 ispivoted at the center of its back at an end 85 b of the L-shaped link85. Using a lever 30, the rotating shaft 81 can be rotated. Using afirst actuator 31, the rod 82 can be moved up and down. The rod 82 isprovided with jaws 82 a so that they vertically sandwich the drive link83. The jaws 82 a lift or lower the drive link 83. The lever 30 isformed at an end of the housing H, which is integrally suspended at thelower end of the rotating shaft 81. The first actuator 31, which issecured to the housing H, lifts or lowers the rod 82 as pivoted on thebearing 31 a so that the rod can rotate. That is, the opening mechanism8 can drive the transfer rail 7 and the lid 5 together. For example, asshown in FIG. 2, the mechanism which opens the lid 5 by lowering the rod82. Then the mechanism operates the lever 30 to rotate the rotatingshaft 81 about 90° together with the housing H, withdrawing the lid 5 atright angles to the direction of transfer, as shown in FIG. 3. Whilewithdrawing the lid 5, the mechanism disposes the transfer rail 7between hearths 60 in the adjacent chambers (1, 2) (2, 3), and (3, 4).Conversely, the mechanism rotates the rotating shaft 81 about 90° in theopposite direction to position the lid 5 so that it faces the opening 5a of each of the treatment chambers 1, 2, 3, and 4. At the same time,the mechanism withdraws the transfer rail 7 so that it is at rightangles to the direction of transfer. Finally, the rod 82 moves up, thuscausing the lid 5 to move until it closes the opening 5 a, as shown inFIG. 1. In FIG. 2, a reference numeral 100 indicates a seal that makes apressure-tight contact between a wall in which the opening 5 a is formedand the lid 5. In FIG. 4, a reference numeral 50 a indicates a seal thatmakes a pressure-tight contact between the rotating shaft 81 and thecontainer through which the rotating shaft 81 passes, and a referencenumeral 50 b indicates a seal that makes a pressure-tight contactbetween the rod 82 and the housing, through which the rod 82 passes.

[0028] Using not only such an arrangement as described above but anurging the mechanism 9 in separating the compartment 6, a continuoustreatment apparatus according to the present invention transfers treatedobjects w one after another. As shown in FIGS. 4 and 5, the urgingmechanism 9 comprises a pair of rack members 91 that can move in thedirection of transfer, a pinion 92 that drives rack members, andlatching means 93 and 94 that selectively engages the rack members 91with a treated object.

[0029] The pair of the rack members 91 is disposed, with their lowerends sliding and fitting into a guide groove 7 a provided in thetransfer rail 7. Rack teeth 91 a are impressed on the opposite surfacesof rack members. The pinion 92, which engages simultaneously with therack teeth 91 a on opposite surfaces, is disposed along the middle ofthe length of the rack members 91. The pinion 92 is coupled with the rod82, which rotates the pinion. That is, in the housing H, the rod 82 isfit with a gear 32 a, which is engaged with a drive gear 32 b. The drivegear 32 b is driven by a second actuator 32. That is, when the firstactuator 31 lifts or lowers the rod 82, the engagement between the gears32 a and 32 b move so that they do not prevent the rod 82 from moving.When the second actuator 32 rotates the rod 82, this rod 82 is rotatablypivoted on the bearing 31 a so that the rod 82 is not prevented fromrotating. When the rod 82 moves up, thus closing the lid 5, the pinion92 can also move up so long as it does not come off rack teeth 91 a.

[0030] As shown in FIG. 6, the latching means 93 and 94 is installed inthe rack members 91 at their both ends. The means is rotatably attachedto the shafts 93 a and 94 a that are installed at right angles to thedirection of transfer. The means is intended to lift upward hooks 93 band 94 b, which are formed on sides of transfer start and transfer end,above top 91 b of the rack members 91 or lower the hooks below the top.The hooks 93 b and 94 b selectively interpose between a tray 10 on whichthe treated object is placed and the rack members 91 to indirectlyengage the rack members 91 with the treated object. Specifically, thehooks 93 b and 94 b have tapered surfaces 93 b 1 and 94 b 1 thatprogressively become higher from side of transfer start to side oftransfer end. As shown in FIGS. 7 and 8, the tapered surfaces 93 b 1 and94 b 1 are placed under the tray 10 to fit the surfaces into recesses 10a, 10 b, and so on that are provided at the front and rear of the tray10. As shown in FIG. 6, the inner ends of the rack members 93 and 94 areelastically urged downward by the leaf spring 95. When hooks 93 b and 94b move down, thus lifting inner ends 93 c and 94 c, elastic energy isstored in the leaf springs 95.

[0031] An application of the embodiment is described below. A sinteredobject w is assumed to be moved from the sintering chamber 3 to thecooling chamber 4, which is empty as shown in FIG. 1. First, a pressureadjusting means, not shown, is used to level pressure in both thetreatment chambers 3 and 4 and separating compartment 6. Then rod 82 islowered using the first actuator 31, and the lid 5 is opened using theL-shaped link 85 (FIG. 2). Next, the housing H is rotated about 90° towithdraw the lid 5. At the same time, the transfer rail 7 is installedbetween the treatment chambers 3 and 4 (FIG. 3). Next, using the secondactuator 32, the pinion 92 is rotated in a direction to move back thefront end of one of the rack members 91, thus placing the ends in thesintering chamber 3, as indicated by a phantom line in FIG. 5. Here, thehook 93 b of the latching means 93, which is provided at the rear end ofthe rack member 91, comes under the tray 10 and catches the recess 10 aat the front end of the rack member 91 (FIG. 7). By reversely operatingthe second actuator 32, the pinion 92 is driven in the reverse directionto move the tray forward using hook 93 b. When the tray 10 reaches aproper position, the other rack member 91, in turn, moves back fartherthan its pair member 91, so that the hook 94 b of the latching means 94,which is provided at the front end of the other rack member 91, comesunder the tray 10 and catches the recess 10 a at the front end (FIG. 8).Again, by operating the second actuator 32 in reverse, the pinion isdriven in the reverse direction, so that the tray 10 is moved fartherforward. Here, the hook 94 of the latching means 94, which is providedat the front end of one of the rack members 91, catches the recess 10 bat the rear end of the tray 10. Again, operating the second actuator 32in reverse drives the pinion 92 in reverse, moving the tray 10 intocooling chamber 4. Then both the rack members 91 are returned to theiroriginal position to close the lid 5.

[0032] If the stroke of the rack members 91 is insufficient, increasingthe number of recesses in the tray 10 so that the direction of rotationof the pinion 92 is frequently reversed at short time intervals to catchthe latching means 93 and 94 can cause the treated object to betransferred in the same manner.

[0033] As described above, in the embodiment, the rack members 91 arelatched or unlatched by the latching means 93 and reciprocated throughthe pinion 92 between the treatment chambers 4 and 3, between thetreatment chambers 3 and 2, and between the treatment chambers 2 and 1.Thus one treated object w after another can be transferred from thetreatment chamber 3 to the treatment chamber 4, from the treatmentchamber 2 to the treatment chamber 3, and from the treatment chamber 1to the treatment chamber 2 without incurring thermal shock to treatedobjects w.

[0034] The urging mechanism 9, which is in the separating compartment 6between the treatment chambers 4 and 3, between the treatment chambers 3and 2, and between the treating members 2 and 1, reciprocates the rackmembers 91 to transfer a treated object w. The rack members 91 and thepinion 92 are mainly in the separating compartment 6, not in thetreatment chambers 4, 3, 2, and 1. Thus the rack members 91 and thepinion 92 are less likely to be exposed to hot treatment gases, so thatmany hours of stable operation can be performed, free of the adverseeffects of thermal shock and treatment gas. In particular, thedisposition of the actuators 31 and 32 completely outside the containereliminates the above-described potential problems. Urging even a longtreated object a plurality of times, with the latching means 93 and 94engaged with the object at a different position, allows the object to beefficiently transferred without large the rack members 91.

[0035] The embodiment uses two rack members 91. While one rack membertransfers the tray 10, the other prepares for the next transfer. Thisallows efficient, high-speed transfer of a treated object w.

[0036] In the embodiment, the lid 5 closes the treatment chambers 4, 3,2, and 1. Again in the embodiment, with the lid 5 open, the transferrail 7 links the treatment chambers 4 and 3, the treatment chambers 3and 2, and the treatment chambers 2 and 1, so that the rack members 91can move along the transfer rail 7. Using such an arrangement, thefollowing two opposite operations are performed around the rotatingshaft 81: (1) when the lid 5 is opened, it is withdrawn to a position atwhich it does not interfere with the transfer rail 7 or the rack members91; and (2) when the lid 5 is closed, the transfer rail 7 and the rackmembers 91 are withdrawn to a position at which the transfer rail 7 andthe rack members 91 do not interfere with the lid 5. Thus hermeticallysealing the treatment chambers 4, 3, 2, and 1 and properly transferringa treated object w are compatible with each other, without interferencebetween mechanisms. This arrangement also allows compact incorporationof the parts. In addition, because the transfer rail 7 is positioned inplace or withdrawn by rotation, the gap between the hearths 60 inadjacent treatment chambers can be minimized, resulting in smoothtransfer.

[0037] The rotating shaft 81 contains rod 82 to open or close the lid 5,withdraw the lid, position the transfer rail in position or withdraw it,drive the urging mechanism 9, and so on. Because the rotating shaft 81needs to penetrate the container at only one point, an apparatus can bearranged using the least complicated seal mechanisms, etc. Because theopening mechanism 8 for the lid 5 and the rotating shaft 81 support eachother in such an apparatus, undue force is prevented from being appliedto the container, a component of the apparatus, when the lid 5 closes.

[0038] Specific part arrangements are not limited to those describedwith reference to the embodiment. For example, only one rack member, nottwo, may be used to transfer a treated object. A lid may be installed ateither the outlet or inlet of a treatment chamber. A clutch mechanismmay be used to rotate both the pinion and transfer rail. Differentshafts may be used for the pinion and transfer rail. To reduce transferresistance, rollers made of a heat-resistance material, such asgraphite, may be installed on the hearth 60 and the tray 10. To protectthe seal 100 from exposure to heat when the lid 5 is opened, it iseffective to employ an arrangement in which a partially circular heatprotecting plate installed on the wall withdraws outside, being pushedby the edge of the lid when the lid closes.

[0039] A cooling water path may be located in the rotating shaft 52 tocool the lid 5. In the above-described embodiment, rotating shaft 90° inthe reverse direction to reverse the hook of the latching means when thelid opens allows the tray to move opposite to the transfer direction.Therefore, this arrangement is effective for sending a tray in and outwhen treatment is performed using an apparatus with two treatmentchambers.

[0040] Other variations can be made without departing from the scope ofthe present invention. For example, the following variations can be madebased on the fact that the urging mechanism used for the above-describedembodiment can easily change the orientation of the tray 10 by therotating shaft 82 when the tray is in the separating compartment 6.

[0041] For example, the preparation chamber and cooling chamber, whichare unlikely be exposed to heat, can be designed as a separatingcompartment, not a treatment chamber. As shown in FIG. 9, a tray shouldbe moved in and out through an opening A3 on a side of a preparationroom Al or a cooling room A2 and transferred after it is rotated 90°. Ahinged door that opens upward or a lid that withdraws upward should beinstalled at opening A3. A long continuous furnace of a straight-throughtype that has an increased number of treatment chambers may be bent 90°in the middle or made U-shaped by bending it twice, as shown in FIG. 10,if the furnace requires too much space. In FIG. 10, the treatmentchamber consists of a preparation room 101, a first dewaxing chamber102, a second dewaxing chamber 103, a sintering chamber 104, and acooling chamber 105. Installing at the bends the transfer rail 7 usedfor the above-described embodiment, which is driven by the rotatingshaft 82, and moving a tray using the urging mechanism 9 attached to thetransfer rail 7 allows the tray to continue to be transferred after itis rotated at the bends. A mechanism that withdraws the lid upward maybe used at the bends.

[0042] A type of continuous treatment furnace has a plurality oftreatment chambers 201 with an opening 201 a facing a central transferchamber 202. The furnace transfers a treated object w through thecentral transfer chamber 202 from one treatment chamber 201 to another.To rotate a tray and transfer a treated object w, transfer mechanism 8and the urging mechanism 9 are effectively used for the transfer chamber202. Of course, four treatment chambers 201 or more may be provided forone central transfer chamber 202. In such a case, the lids have only tobe designed to withdraw upward.

[0043] Alternatively, a variation of the means for reciprocating atreated object may be used. The variation has bars with latches disposedon the hearth of the treatment chambers, and these bars can slide backand forth. These bars combine with those in the separating compartmentsto form one long bar when the racks in the separating compartments areplaced in between. The variation is possible to reciprocate all barssimultaneously using linear cylinders provided at the inlet and outletof the continuous furnace to transfer a treated object forward. Becauseall bars reciprocate at the same time, all treated objects are alsotransferred at the same time. Thus the apparatus cannot stand by, withthe preceding treatment chamber kept empty. However, the variation maybe effective, depending on a treating process or an furnace application.

[0044] Because the present invention are arranged as described above,the components of the transfer mechanism are less likely to be exposedto high temperatures, compared with pusher chain type apparatuses. Theinvention, in which the components can be protected from damage due tothermal shock and treatment gas, also feature extended service lives,eliminating the need for maintenance and reducing operating costs.Reciprocating rack members according to the size of a treated objectallows effective transfer even for long objects. Thus the apparatus doesnot need to be enlarged. This results in lower initial cost andspace_savings.

[0045] An arrangement that allows the lid to be opened or closed and thetransfer rail to be moved in and out by rotation about the shafts sothat the lid and rail do not interfere with each other reduces the sizeof the drive mechanism and its peripheral parts, increasing transferstability and reliability.

What is claimed is:
 1. A continuous treatment apparatus adapted so thata treated object can be transferred from a treatment chamber to the nexttreatment chamber using urging mechanisms between a plurality oftreatment chambers, wherein the urging mechanisms have the rack membersthat can move in the direction of transfer, a pinion which drives therack members and latching means for selectively engaging the rackmembers with the treated object; and wherein the rack members are notonly engaged or disengaged with the treated object using the latchingmeans, but reciprocated between adjacent treatment chambers through thepinion to transfer the treated object from one treatment chamber toanother.
 2. A continuous treatment apparatus according to claim 1 ,wherein the rack members are provided in pair and a pinion is engagedwith the rack members at the same time and the following operation isrepeated: while one of the rack members moves forward to transfer atreated object, the other moves back in preparation for the nexttransfer, and vice versa.
 3. A continuous treatment apparatus accordingto claims 1 or 2, wherein the latching means is provided at a pluralityof positions along the direction of transfer of a treated object by therack members.
 4. A continuous treatment apparatus according to any ofthe preceding claims, wherein the latching means is engaged with atreated object at a plurality of positions along the direction oftransfer of the treated object.
 5. A continuous treatment apparatusaccording to claim 1 , wherein the apparatus is so adapted so that eachtreatment chamber can be opened or closed by a lid, that rack memberscan move along the transfer rail which links adjacent treatment chamberswith the lids open, and that the following opposite operations can beperformed around the rotating shaft: (1) when the lid is opened, it iswithdrawn to a position at which it does not interfere with the transferrail or rack members; and (2) when the lid is closed, the transfer railand rack members are withdrawn to a position at which the rail and rackmembers do not interfere with the lid.
 6. A continuous treatmentapparatus according to claim 5 , wherein the lid, the transfer rail, andthe rack members are installed and withdrawn using a common rotatingshaft.
 7. A continuous treatment apparatus according to claim 6 ,wherein a rod is housed in the rotating shaft, and the rod ascends ordescends to open or close the lid.
 8. A continuous treatment apparatusaccording to claim 7 , wherein a pinion is connected with the rod, andthe rod can be rotated without being prevented from ascending anddesceding.